NAMSW · Insider Trading
NewAmsterdam Pharma Company N.V. Warrant
Every open-market purchase and sale reported by NAMSW officers, directors and 10%+ beneficial owners on SEC Form 4, which must be filed within two business days of the transaction. Sales often reflect scheduled 10b5-1 plans or tax withholding rather than a directional view, so read counts alongside the size and the filer.
| Filed | Insider | Role | Type | Shares | Value |
|---|---|---|---|---|---|
| 2026-05-27 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | −$1.67M |
| 2026-03-12 | Louis G Lange | Director | Sell | −44,619 | −$1.36M |
| 2026-03-10 | Louis G Lange | Director | MIXED | +16,433 | −$315.83K |
| 2026-03-09 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | MIXED | — | −$9.09M |
| 2026-03-02 | Michael H. Davidson | Chief Executive Officer | MIXED | — | −$14.75M |
| 2026-02-26 | Michael H. Davidson | Chief Executive Officer | MIXED | — | −$10.58M |
| 2026-02-24 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | Sell | −45,481 | −$1.61M |
| 2026-01-29 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | −$1.55M |
| 2026-01-27 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | −$1.62M |
| 2026-01-22 | Mayur Ian Somaiya | Chief Financial Officer | MIXED | — | −$2.33M |
| 2026-01-09 | Louis G Lange | Director | A | +3,400 | — |
| 2026-01-09 | William Lewis | Director | A | +3,400 | — |
| 2026-01-09 | Adele M. Gulfo | Director | A | +3,400 | — |
| 2026-01-09 | Kamp Hilde Johanna van der | Director | A | +3,400 | — |
| 2026-01-09 | John W Smither | Director | A | +3,400 | — |
| 2026-01-09 | Michael H. Davidson | Chief Executive Officer | MIXED | +69,418 | — |
| 2026-01-09 | Mark C. McKenna | Director | A | +3,400 | — |
| 2026-01-07 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | +9,353 | −$88.01K |
| 2026-01-07 | Mayur Ian Somaiya | Chief Financial Officer | MIXED | +20,382 | −$170.17K |
| 2026-01-07 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | MIXED | +19,500 | −$199.50K |
| 2025-12-29 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | −$3.74M |
| 2025-09-17 | James N Topper | Director | Buy | +660 | +$15.64K |
| 2025-09-10 | Louise Frederika Kooij | Chief Accounting Officer | MIXED | — | −$2.37M |
| 2025-09-10 | James N Topper | Director | Buy | +1,260 | +$31.49K |
| 2025-09-05 | Louise Frederika Kooij | Chief Accounting Officer | Sell | −18,073 | −$453.45K |
| 2025-09-04 | Louise Frederika Kooij | Chief Accounting Officer | M | +18,073 | — |
| 2025-08-27 | Louise Frederika Kooij | Chief Accounting Officer | Sell | −8,269 | −$205.57K |
| 2025-08-25 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | Sell | −100,000 | −$2.47M |
| 2025-08-13 | James N Topper | Director | Buy | +471 | +$11.29K |
| 2025-07-17 | Douglas F Kling | Chief Operating Officer | MIXED | — | −$1.02M |
| 2025-06-26 | James N Topper | Director | Buy | +3,780 | +$69.47K |
| 2025-06-18 | James N Topper | Director | Buy | +8,584 | +$167.38K |
| 2025-06-18 | Douglas F Kling | Chief Operating Officer | MIXED | — | −$909.43K |
| 2025-06-03 | Louis G Lange | Director | M | +68 | — |
| 2025-06-03 | Michael F Marino III | See Remarks | A | +55,000 | — |
| 2025-05-19 | Douglas F Kling | Chief Operating Officer | MIXED | — | +$1.00M |
| 2025-05-02 | Juliette Berangere Audet | See Remarks | A | +30,000 deriv. | — |
| 2025-05-02 | Louis G Lange | Director | M | +69 | — |
| 2025-04-21 | Louis G Lange | Director | M | +69 | — |
| 2025-04-17 | Douglas F Kling | Chief Operating Officer | MIXED | — | +$1.00M |
| 2025-04-17 | Adele M. Gulfo | Director | A | +10,860 | — |
| 2025-03-28 | Louis G Lange | Director | M | +3,102 | — |
| 2025-03-28 | James N Topper | Director | Buy | +1,135 | +$25.52K |
| 2025-03-28 | Douglas F Kling | Chief Operating Officer | MIXED | — | — |
| 2025-03-28 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | MIXED | +64,783 | — |
| 2025-03-28 | Michael H. Davidson | Chief Executive Officer | MIXED | +57,128 | — |
| 2025-03-28 | Louise Frederika Kooij | Chief Accounting Officer | M | +8,269 | — |
| 2025-03-26 | Johannes Jacob Pieter Kastelein | Chief Scientific Officer | M | +150,000 | — |
| 2025-03-19 | Douglas F Kling | Chief Operating Officer | MIXED | — | +$118.88K |
| 2025-03-06 | James N Topper | Director | Buy | +4,005 | +$84.20K |
| Insider | Role | Shares Held | Value |
|---|---|---|---|
| Forbion Capital Fund IV Cooperatief U.A. | 10%+ Owner | 11,778,760 | $97.17M |
| Forbion Growth Management B.V. | 10%+ Owner | 11,339,949 | $93.55M |
| ForGrowth NAP B.V. | 10%+ Owner | 10,760,928 | $88.78M |
| Forbion IV Management B.V. | 10%+ Owner | 10,686,018 | $88.16M |
| Forbion Growth Opportunities Fund I Cooperatief U.A. | 10%+ Owner | 10,656,172 | $87.91M |
| James N Topper | Director | 3,801,000 | $31.36M |
| Michael H. Davidson | Chief Executive Officer | 459,859 | $3.79M |
| Johannes Jacob Pieter Kastelein | Chief Scientific Officer | 153,591 | $1.27M |
| Mayur Ian Somaiya | Chief Financial Officer | 58,382 | $481.65K |
| Michael F Marino III | See Remarks | 55,000 | $453.75K |
| Douglas F Kling | Chief Operating Officer | 47,544 | $392.24K |
| William A Jones Jr | Chief Commercial Officer | 43,000 | $354.75K |
| Louise Frederika Kooij | Chief Accounting Officer | 24,353 | $200.91K |
| Juliette Berangere Audet | See Remarks | 15,104 | $124.61K |
| Adele M. Gulfo | Director | 14,260 | $117.64K |
| Mark C. McKenna | Director | 10,360 | $85.47K |
| John W Smither | Director | 10,360 | $85.47K |
| William Lewis | Director | 10,360 | $85.47K |
| Kamp Hilde Johanna van der | Director | 10,360 | $85.47K |
| Louis G Lange | Director | 10,360 | $85.47K |
Form 4 reports a change in beneficial ownership by an officer, director or 10%+ holder, and must be filed within two business days of the transaction — so this is close to real time, unlike the 45-day-lagged 13F institutional data.
Transaction codes matter more than the raw buy/sell count. Code P is an open-market purchase — an insider choosing to buy with their own money, which is the signal most research treats as informative. Code S is a sale, but sales are frequently pre-scheduled under a 10b5-1 plan or cover tax withholding on vesting equity, so a run of sales often says nothing directional. Codes A and M are grants and option exercises rather than open-market decisions.
Full filing history and per-insider positions are on the NAMSW quote page; the site-wide leaderboard is on the insider transactions hub.
Market data may be delayed, incomplete, or inaccurate. Not a recommendation to buy, sell, or hold any security. Verify quotes with your broker before trading. See Terms §17.